Variable-resistance



A. A. ZEEGLER.

VARIABLE RESISTANCE UNlT. APPLICATION FILED SEPT. 22, I914.

l ,32 1 ,873 Patented Nov. 18, 1919 2 SHEETS-SHEET l.

A. A. ZIEGLER.

VARIABLE RESlSTANCE UNIT.

APPLICATION FILED SEPT. 22. 1914.

1 321,873. Patented Nov. 18, 1919.

' 2 $HEETSSHEET 2- Zbiizzeases:

PATENT OFFICE.

1 human a. or cosmos, massacnusnrrs.

Specification of Letters Patent.

VARIABLE-RESISTANCE U'mr.

- Patented Nov.18, 1919.

Application fled September 22, 1914. Serial No. 863,049.

,To all whom it may concern;- Be it known that I, Amman A. Zmomn, a citizen of 'the United States, residing at Boston, in'the county of Su'flolk'and State of Massachusetts,- have invented an Improvement in Variable-Resistance Units, of which the following is a s ification.

This invention re ates to a variable resistance-unit, and has for its object the construction of a simple form of varying-means which may be applied as an attachment to a resistanceclement, and, is particularly designed to be applied to the resistance-element o No. 824,923, filed March 16,1914. The varying-means-involves a contact-member for engaging theresistance-element at any desired I pomt, which member may be cons rncted 1n various ways, and a support for said membox, which is detachably connected with the resistance-unit, and means to slidably connect said member to its support, whereby it may be adjusted to any desired position with respect to the resistance-element., The frame bearing the contact-member is coextensive with the length of the resistance-element, and is ada tedto be detachabl connected to one of jihetenninal-plates 0 the resistance-element, and in the-particular embodiment of my invention here shown for illustration, wherein the resistance-element involves a spool of insulating material and a; resistance-wire coiled thereon and terminalplates projecting from the ends of said spool, oneend of said supporting-frame may' be connected, preferably. detachahly, with a terminal-plateat oneen'd of the spool ,and its other end arranged for engagement with the other end of the spool.

F" re 1 is a side-elevation of avariaole resistance-unit embodying this invention. Fig. 2 is a' lan view of the same.,;.

- 3 is a ongitudinal vertical section of the same.

positiomfi a i Fig. 6 isa1s1de-elevation of'a variable are- 60 vsistaxme-unit having a modified form of con- I 7 isan enl rged sectional detail view of the contact-member of 6.3" a 1 Fig.8 a siderelevation o a variable resista'noe-unit having wam-m me my applieationfor Letters Patent, Serial sistance element.

eomprises'a spool 25,.composed of insulating ,4 and. 5 are sectional detail views of the cohtactimembenits sup rt and means, for holding thecontact-niem "r in adjusted era 1y,-fromend to end thereof.- Ashore V 43, -t lfat' one end thereb another'f modified form Fig. 9 is an enlarged sectional detail view of the contact-member of Fig. 8.

' Fig. 10 is a modified form of variable resistance-unit having varying-means embodythisinvention.-

in in the embodiment of my invention shown in Figs. 1 to 5 the means for varying the resistance is shown as applied to the resistonce-unit of my application 124,923, aforesaid, wherein 10 represents a se of insnlat ing materially such as rcelain, and i4 screws having nuts 'suitab y arranged thereon to constitute binding-posts; 20, 20 represent flat supporting-plates which are arranged on'the binding-posts, said lates hav 'ing end-portions which are exten ed toward each other. Said end-portions have holes through them fox-screws .22 for the. connec tion t erewith of the terminals of the re- 76 The: resistanceelement material, as porcelain, on which. one or more layers of resistance-wire are woimd, and said spool has sockets at its ends which receive tenninal-plates' 30, and the ends of the coil of wire are connected to said terminallates. The terminaLplates have transve y' arranged recesses'35, in their sides'to admit of their -engagement with the shanks of the screws 22, on the sup rting-plates; or fordirect engagement wit the binding-posts as represented in Fig. 10. The resistance-element is therefore (letacha'bly connected with its su port. This form of resistance-element is here shown for the reason that-m improved varying-means is especiallywe suited for attachment thereto, but obviously the var ing-mean's'maybenttached to otherv shown-said'snpportingirameis oi sheet-Inetal'which 'is-qnt and'bntto'the desired-form. It has two ri'ght-angle'bends pmv dm a end-portion" or car 46, hich ,end rtion has a transverse recess in one side 0 it,-adtfilttiiig -of itsengageme il f with the shank 6f the screw-22. on a -supporting-.pl ate to z lot means for holding its end opposite its point of attachment with the terminal-plate in fixed position, and. as here shown, said endportion of the frame is bent downward at tended finger 65, and said bent portion of the frame extends over the end of the spool for a short distance, and its fin er-is arranged to enter a small hole Win51 may be formed in the end of said spool. This means of holding said end of the'framc also admits of its readyatta'chment to and detachment from the spool. And said support has a nut 62 thereon which may be turned thereby to secure the support in any position on the frame which it may be set.

As-represen'tecl in-Figs. .1 to, 5. and Fig. 10, the contact-member is composed of sheet metal and 'bent to form a curved finger, the free end of which has a small notch to enable its end portion to engage the wire, of the resistance-coil, and the other end of said finger is carried over and around the frame 42,

to form a loop. which embraces'thesframe,

thereby to-permit of itssliding connection therewith, and said. end-portion of the finger has'holes through it for a screw 41, and

saidscrew extends through and is movable v is var thatthe' supporting-frame is designed for- .attachment' to t-h'eresistanceunit, it will be along a slot 50$.which is formed throughout the length of the'supportinq-frame 42, and a nut.62, is arranged on said screw. As the screwis moved along the slot 50 the curved contact-member or finger is moved by it. Said contact-finger, being composed of sheet metal, and bent, as shown, 'is yielding, so that it yieldingly engages the resistance-element with a firm pressure to insure a good contact therewith. Vhen the nut 62 is turned down tightly said contact-finger is pressed into firm engagement with the wire, as well as being securely held in its different p0. "tions of adjustment. The resistance Rd by moving thecontact-member along its supporting-frame toie'ngage the resistance-wire 'at different 'poiiits. The structuralv form of varying-means here shown possesses manyadvantages on account of its simple character and fease of ati tachment 'to the resistance-element;

1 1 In-viewof the factthatthe contact-meni her is slidablylarinnged' on the supporting frame, and that the'means for holding fixed position are associated with lid and seen that? the"entirevar ing-means may maderassembled and sol as a separate unit,

member consists of a contact-screw 7 0, passing through a nut 71, which is slidably connected with the supporting-frame 42, and

the end of said screw is arranged for en- 63 and inward at 64, and has an inwardly exgagement with the resistance-wire; and .referring to Figs; 8 and 9 the contact-screw 80 passes up throu h the slot 50 in the .supporting-frame, and has a nut 81 arranged upon it, and said nut engages the upper side of the supporting-frame, while beneath said frame a spring is arranged on the contact-screw, the upper end of which bears against the upper end of a housing 83 and incloses the lower end-portion of the contact-screw, and the lower end of which bears against a flange or washer on the screw, and the-tendency is for the spring to thrust'the contact-screw into yielding engagement with the resistance-wire while the nut holds it in sliding engagement with the supportingframe. In this latter modification upon turning up the nut the contact-screw is raised free from the engagement with the wire, yetits connection with the supportingme, by reason of the spring bearing frame being out of the resistance circuit when the member is free of connection with the resistance element, and means to slidably connecti said member with said frame, substantia ly as described.

2. In a variable resistance-unit, the com-- bination v u a resistance-element having terminal-plates, of a manually operable contact-member arranged it'or engagement with and disengagement from the resistance-element, an elongated slotted supporting-frame extended over the resistance-element and having one end arranged for detachable connection with one of the terminal-plates, the opposite end of the frame being at all times free from electrical connection with the circuit including the resistance element, and means t-o slidably connect said member with said slotted fra'me, substantially as described.

nation with a resistance-element having tern'iinal-plates, of a manually operable contactancinbei' made as a curved finger, one end of which is arranged for slidable connection with its enpporting frame and its free end is arranged for engagement with and disengagement from the resistance-element, an elongated slotted snpportingdraine (Zitti'xClG'll 0115. said resistanceclement and arranged for detachable connection with one of the termfinal-plates and means for moving said contact-member along on lts supportingotrame and for holding it in any position it may he sehsnlzstantially as desciibe 4. In a variable resistanceunit, the combination with spool and coil of Wire thereon, terminahplates at the ends of said spool to which the ends of said wire are attached, of a contact-member arranged for engagement with said wire, a supporting-frame for said member which is extended over and arranged lengthwise of said spool and is arranged for detachable connection with one of the terminal-plates, and means to slid-.

said frame,

ably connect said member with substantially as described;

5. In a variable resistanceunit, the combination. with aspool and coil of wire there on, termii'ial-plates at the ends of said spool to which the ends of said wire are attached, of a contact-member arranged for engagement with said wire, a supportingdrame for said contactcnember which. is extended over which the ends of said wire are attached, of a contact-member arranged for engagement with said wire, an elongated slotted supporting-frame for said contact-member which is extended over and arranged lengthwise said spool, and has a recessed carat one end for detachable connection with one of the terminal-plates, and-has an inturned finger. at its other end for engagement with the spool and means to slidably connect said member with said frame, substantially as described.

7. In a variable resistance-unit, a base haw ing binding-posts ranged thereon, and hav- 11 1g supporting-p res connected with said b1nd1ng-posts, a resistance-element having terminal-plates for detachable connection with said supporting-plates, a contact-memnut for holding the guide to the bar and permitting adjustment. of the contact to different convolutions of the coil.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

' ALFRED A. ZIEGLER.

Witnesses: I

B. J. Noyes, B. DAVIS.

' extending below the guide, and a screw and 

